Peter O'Mahony admits the Ireland squad were taken aback when CJ Stander informed them of his decision to retire.
The 31-year old made his decision public on Tuesday morning, having told his international teammates the night before.
O'Mahony and Stander have almost a combined 300 Munster appearances to their name, while on the international stage started every game together in Ireland's Grand Slam-winning year of 2018 and were teammates on the 2017 Lions tour to New Zealand.
"Very shocked, obviously, when he told us all last night," O'Mahony said of Stander's decision.
"Obviously didn't see it coming - I don't think anyone did - but he explained his reasons and his reasons are very valid ones, very noble ones in my opinion.
"Everyone will respect his decision. The man has given an incredible amount to, not just Ireland, but to Munster as well, [and] Limerick.
"[He's an] incredible teammate, and he's got to give a bit back to his family now who've sacrificed a huge amount for him.
"Look, we'll hopefully make this week and the 3-4 months he has remaining left to play with us, and me certainly, as special as we can."
Asked what set Stander apart from other players, O'Mahony was effusive in his praise, pointing to, "His selflessness, his professionalism... From the day he arrived in Munster he did his best to buy-in to our culture and now he's creating bits of our culture.
"He's a person who I'd always think 'who do kids look up to?'. You want to be someone who the young fellas look up to.
"I suppose it's a nice compliment to give someone that there's kids around - probably not just Ireland, around the British Isles and beyond - who want to be like CJ.
"He's an incredible family man, which obviously he's spoken about and how important that is to him.
"[He's] An incredible friend and obviously an incredible teammate, but more importantly an incredible friend and I can't say much more."
With O'Mahony set to return to the Ireland side for Saturday's Six Nations finale against England, it will likely mark the pair's final outing together in the green jersey.
On the provincial front, Munster still have a Guinness PRO14 Grand Final against Leinster on March 27, followed by a Heineken Champions Cup last-16 tie with Toulouse.
O'Mahony says Stander's impact around the club won't be easy to replace.
"You see the way he turns up every week," he said, "It's no secret that he's never had a long-term injury, or any sort of injury at all, and that's down to how he looks after himself, his professionalism, his recovery.
"He brings an incredible edge - not just when it comes to the weekend, but in training as well. He's an immaculate trainer.
"Incredibly coachable, which is something also that I would rate him as one of the best. His ability to listen and learn, and to learn new skills.
"The player he arrived at, and the player he is now, he's come such a long way and he's lapped up the great coaches that himself and myself have spent a huge amount of time with.
"Again, just a competitor. We've all watched him play 50-odd times for Ireland, and well over 100 for Munster.
"He's just competing and competitive with everything and that's what made him such an incredible teammate."